Nokia Using Radio Waves to Potentially Charge Mobile Phones

Nokia researchers are describing a new and innovative method for using the radiation of ambient radio waves in order to charge a range of mobile devices, including cell phones and smartphones.

On the Nokia Conversations blog, the company offers a look at how researchers are using a prototype device that is capable of collecting about 3.5 milliwatts of power from the electromagnetic radiation found in Wi-Fi devices, mobile phone antennas and television masts.

The goal, according to the June 10 blog post from Nokia, is to eventually create a device that can collect up to 50 milliwatts of power, which would be enough energy to recharge a cell phone that has run out of power and is turned off.

However, the Nokia researchers caution that they are only experimenting with this type of technology and an actual working model for consumer and business use could be years off. Some researchers believe the technology might never work at all.

A longer version explaining the details of what Nokia's Research Centre scientists are working on can be found at the MIT Technology Review Website. The research is being headed by Nokia researcher Markku Rouvala.

The power-charging concept is based on similar technology found in RFID (radio-frequency identification) tags. The key to the technology is converting electromagnetic waves into electrical signals, which requires two passive circuits.

"Even if you are only getting microwatts, you can still harvest energy, provided your circuit is not using more power than it's receiving," Rouvala told Technology Review.

Now, Nokia researchers are looking to increase the range of frequencies these devices can draw power from in order to increase the amount of energy they can collect. Researchers are now looking at frequencies from 500MHz to 10GHz.

Right now, this type of technology is used to charge small devices such as RFID tags and wireless sensors.

In order to achieve the 50-milliwatt threshold, scientists believe that a device would have to collect about 1,000 strong signals from a wide range of frequencies, which means that a viable consumer device is still a long way from coming to the commercial market.

Nokia is not the only company making headlines about new types of energy efficient technology. On June 10, Google and some partners announced that they are closer to developing new types of renewable energy that are cheaper than coal. Google plans on developing a system that uses this energy in a few years.